Sappers deal with withdrawal (7)
I believe the answer is:
retreat
'withdrawal' is the definition.
(retreat is a kind of withdrawal)
'sappers deal' is the wordplay.
'sappers' becomes 're' (Royal Engineers).
'deal' becomes 'treat' (I've seen this before**).
're'+'treat'='RETREAT'
'with' acts as a link.
(Other definitions for retreat that I've seen before include "Monastery - bugle call" , "Tree rat (anag)" , "Climb down" , "Take flight" , "Pull back" .)